With recent advances of electronic equipment, in the wiring substrate in the electronic component device used for the electronic equipment, the miniaturization and the higher performance, etc. are demanded. In order to respond to such demands, the electronic component built-in substrate in which the electronic component is built in the wiring substrate have already been put to practical utilization.
In one example of such electronic component built-in substrates, the upper wiring substrate is stacked on the lower wiring substrate on which the semiconductor chip, or the like is mounted via the bump electrodes, and then a molding resin for sealing the semiconductor chip is filled into a clearance between the lower wiring substrate and the upper wiring substrate.
A related art is disclosed in Japanese Laid-open Patent Publication No. 2008-10885, Japanese Laid-open Patent Publication No. 2001-210954, and Japanese Laid-open Patent Publication No. 2004-165318.
As explained in the column of the preliminary matter described later, in the electronic component built-in substrate in which the upper wiring substrate is stacked on the lower wiring substrate, on which the semiconductor chip, or the like is mounted, via the solder balls, it is necessary to set a diameter of the solder ball larger than a height of the semiconductor chip. Therefore, to the demand that a quantity of signal is increased with the higher performance of the semiconductor chip, it is difficult to narrow an arrangement pitch by making a diameter of the solder balls small.
Also, when a molding resin is filled into an area between the lower and upper wiring substrates, in the case that an interval between the molding dies is wider than the designed value, the lower and upper wiring substrates are forced to expand. Thus, the solder balls are separated from the lower wiring substrate, and thereby the electrical connection between the lower and upper wiring substrates becomes open.
Conversely, in the case that an interval between the molding dies located to the lower side and the upper side is narrower than the designed value, since the upper wiring substrate is pushed downward more than the necessity, the solder balls are crashed.